Sometime between 2267 and 2270, Spock becomes commander-in-chief of the Terran Empire and implements several major reforms, turning the Empire into a more peaceful and less aggressive power. Prior to the full enactment of these reforms, the Terran Empire forces occupy Bajor. Spock's reforms leave the Empire unprepared to fight against the Klingon-Cardassian Alliance. The Alliance conquers the entire Terran Empire, enslaving the Terrans and Vulcans. (DS9: "Crossover")